1. Field of Invention
The present invention relates to a fan and, in particular, to a fan with the function of preventing the blade loosing.
2. Related Art
The flat electronic computing device such as the notebook computer or tablet computer is usually configured with the build-in powerful high-speed processor. The operating processor may generate heat, which should be removed by proper heat-dissipating component (e.g. a fan) for maintaining the stable operation of the computing device.
Regarding to a notebook computer, in order to achieve the purpose of more compact size and portability, it usually adopts a centrifugal fan for heat dissipation. However, the shaft of the fan may tilt or loose due to collision or the heat-dissipation design during the carrying or putting down of the notebook computer. For solving this issue, as shown in FIG. 1, a fan 1 includes a housing 11, an impeller 12, a fasten ring 13, and a stator 14. The impeller 12 and the stator 14 are disposed in the housing 11. The impeller has a hub 121, a plurality of blades 122 disposed on the periphery of the hub 121, and a shaft 123 matched with the bearing 141 of the stator 14. The fasten ring 13 is disposed in a recess 1231 of the shaft 123 and attached to the bearing 141. The function of the fasten ring 13 is to limit the shaft 123 so as to prevent the impeller 12 from loosing during the rotation.
However, the above-mentioned configuration for limiting the impeller 12 must prepare the sufficient space for configuring the fasten ring 13. In other words, for configuring the fasten ring 13, the length of the shaft 123 must be long enough or the length of the bearing 141 must be reduced. If the length of the shaft 123 is long enough for configuring the fasten ring 13, the product may not be properly minimized. If the length of the bearing 141 is reduced, the duration of the fan 1 may decrease. In addition, the additional fasten ring 13 can increase the total manufacturing cost.
Therefore, it is an important subject of the present invention to provide a fan that can reduce the length of the shaft without affecting the fan property and structural strength and thus make the fan thinner.